Carton

Easily box your Ruby

Carton is a thin wrapper around Ruby::Box for safe, ergonomic modularization in Ruby 4+. It gives you imports and exports that feel like ES Modules while still reading like Ruby. Each carton can isolate constants, gems, and monkey patches behind a small public API, so large apps can keep clear boundaries.

Minimal usage

# user.rb
class User
  def initialize(name) = @name = name
end

export_default User

# main.rb
require 'carton'

User = import_relative 'user'
alice = User.new('Alice')

Named exports return a namespace-like module:

# math.rb
def add(a, b) = a + b

export PI: 3.14159, add: method(:add)

MathTools = import_relative 'math'
MathTools::PI
MathTools.add(2, 3)

Docs

• USAGE.md - detailed import/export, load path, and Bundler usage
• DESIGN.md - implementation overview and constraints
• TODO.md - future improvements and Bundler upstream ideas
• examples/minimal/README.md - smallest example
• examples/complex/README.md - multi-carton example

Development

bundle install                        # Install development deps
RUBY_BOX=1 bundle exec rake           # Run all tests and examples
bundle exec rake format               # Format code

License

Available as open source under the MIT License.